1. Field of the Invention
The present invention relates generally to the field of Helicobacter-based vector, plasmid vector and shuttle vector systems, as novel Helicobacter constructs that include a non-Helicobacter pharmacologically active molecule of interest are provided. The invention also relates to the field of drug delivery, vaccines and treatment methods, as compositions that provide for the administration and/or delivery of non-Helicobacter molecules at the mucosa in vivo are disclosed.
2. Related Art
Helicobacter pylori are a gram-negative spiral shaped bacterium found almost exclusively in the human gastric mucosa. The acidity of the human stomach is an effective barrier to colonization by essentially all bacteria, with the exception of Helicobacter species.
H. pylori have been described as a causative agent of chronic infection. In particular, Helicobacter has been established to play a critical role in peptic ulcer, gastric adenocarcinoma, and primary gastric lymphoma.
H. pylori have the unique ability to colonize and persist for decades within the human gastric mucosa, despite development of a mucosal inflammatory and immune response. This characteristic renders H. pylori an interesting candidate for the delivery of selected agents though the mucosa. However, this particular application has not found application in mucosal delivery systems in part owing to its involvement in a variety of diseases. A need continues to exist for a delivery system employing these important organisms having a reduced risk of pathology to the host.
The development of mucosal vaccines has also been hindered by the poor immunogenicity of antigens delivered by conventional approaches because of natural barrier functions of the host that prevent access to the mucosal compartment. Hence, a need continues to exist in the medical arts for improved delivery mechanisms for pharmacologically active molecules at the mucosal surface sufficient to elicit a useful and beneficial immunogenic response. Such would provide an effective in vivo delivery system for pharmacological active agents, as well as an effective method for immunization, i.e., antigen exposure at a mucosal surface sufficient to elicit a general humoral and mucosal immune response.